CN113499176A

CN113499176A - Coupling unit for medical device delivery system

Info

Publication number: CN113499176A
Application number: CN202110775400.XA
Authority: CN
Inventors: A·内格斯瓦兰; C·党; A·巴雷特; J·范
Original assignee: Covidien LP
Current assignee: Covidien LP
Priority date: 2017-01-19
Filing date: 2018-01-19
Publication date: 2021-10-15
Anticipated expiration: 2038-01-19
Also published as: JP2020512045A; US11833069B2; KR102292314B1; EP3570791A1; KR20190086725A; US10376396B2; WO2018136789A1; CN110225729A; JP7041202B2; US20180200092A1; JP6780118B2; JP2020168454A; CA3046101A1; CN113499176B; US10945867B2; EP3570791B1; CA3046101C; US20210154033A1; US20190336312A1; CN110225729B

Abstract

A stent coupling for a medical device delivery system is disclosed. A stent delivery system includes a core member having a distal section and a link positioned around the core member distal section. The coupling is rotatably coupled to the core member and includes a rigid plate having a first end face, a second end face, and a side surface extending between the first and second end faces, the side surface including one or more projections separated by recesses. The delivery system further includes a stent extending along the core member distal segment such that an inner surface of the stent is engaged by the one or more projections of the engagement member.

Description

Coupling unit for medical device delivery system

The present application is a divisional application of an invention patent application having an invention name of "coupling unit for medical device delivery system", international application date of 2018, 1 month and 19 days, international application number of PCT/US2018/014510, national application number of 201880007614.9.

Cross Reference to Related Applications

This application claims priority from U.S. application No. 15/410,444 filed on 19/1/2017, which is incorporated herein by reference in its entirety.

Background

Walls of the vasculature, particularly arterial walls, can form areas of pathological dilatation called aneurysms, often with thin, weak walls that are prone to rupture. Aneurysms are generally caused by weakening of the vessel wall due to disease, injury, or congenital malformations. Aneurysms occur in different parts of the body, and are most commonly abdominal aortic aneurysms and cerebral (e.g., cerebral) aneurysms in the neurovasculature. Death may result when the weakened wall of the aneurysm ruptures, particularly when the cerebral aneurysm wall ruptures.

Aneurysms are typically treated by excluding a weakened portion of a blood vessel from, or at least partially isolating, the arterial circulation. For example, conventional aneurysm treatments include: (i) surgical clamping, in which a metal clip is secured around the base of an aneurysm; (ii) bundling aneurysms with small flexible wire coils (microcoils); (iii) "filling" the aneurysm with embolic material; (iv) occluding a parent vessel supplying an aneurysm using a detachable balloon or coil; and (v) endovascular stenting.

Endovascular stents are well known in the medical field for the treatment of vascular stenosis or aneurysms. A stent is a prosthesis that expands radially or otherwise within a vessel or lumen to support the vessel from collapsing. Methods for delivering these intravascular stents are also well known.

Conventional methods of introducing a compressed stent into a blood vessel and positioning it within a stenotic region or aneurysm include: the distal portion of the guide catheter is percutaneously advanced through the vascular system of the patient until the distal portion is proximate the stenosis or aneurysm. A second inner catheter and a guidewire within the inner catheter are advanced through a distal region of the guide catheter. The guidewire is then advanced out of the distal region of the guide catheter into the vessel until the distal portion of the guidewire carrying the compressed stent is positioned at the lesion site within the vessel. The compressed stent is then released and allowed to expand so that it supports the vessel at the site of the lesion.

Disclosure of Invention

The present techniques are illustrated, for example, in accordance with various aspects described below. For convenience, various examples of aspects of the present technology are described as numbered clauses (1, 2, 3, etc.). These are provided as examples and do not limit the present technology. It should be noted that any dependent clause may be combined into any combination and placed into the corresponding independent clause (e.g., clause 1 or clause 23). Other terms may be presented in a similar manner.

1. A stent delivery system, comprising:

a core member having a distal section;

a coupling positioned about the core member distal segment and rotatably coupled to the core member, the coupling comprising a rigid plate having a first end face, a second end face, and a side surface extending between the first and second end faces, the side surface comprising one or more projections separated by recesses; and

a stent extending along the core member distal segment such that an inner surface of the stent is engaged by the one or more protrusions of the link.

2. The stent delivery system of clause 1, wherein the protrusion comprises a rounded edge.

3. The stent delivery system of clause 1, wherein the one or more tabs comprises three or more tabs.

4. The stent delivery system of clause 1, wherein the longest dimension of the first end face and the second end face is configured to fit within a 0.017", 0.021", or 0.027 "inner diameter catheter.

5. The stent delivery system of clause 1, wherein a maximum length of the first and second end surfaces is at least 5 times greater than a length of the side surface, the maximum length of the first and second end surfaces being substantially orthogonal to the length of the side surface.

6. The stent delivery system of clause 1, wherein the rigid plate comprises at least one of a metal or a rigid polymer.

7. The stent delivery system of clause 1, wherein the rigid plate side surface has a length of between about 25 microns-100 microns.

8. The stent delivery system of clause 1, wherein the rigid plate is a first rigid plate, the stent delivery system further comprising:

a second rigid plate positioned around the core member distal section and spaced apart from the first rigid plate; and

a spacer positioned around the core member distal segment, the spacer positioned between the first rigid plate and the second rigid plate.

9. The stent delivery system of clause 8, wherein the spacer comprises a cylindrical body having an end wall orthogonal to the long axis of the core member.

10. The stent delivery system of clause 8, wherein the first rigid plate and the second rigid plate are spaced apart from each other by a distance corresponding to an aperture spacing of the stent.

11. The stent delivery system of clause 1, wherein the first end face and the second end face are substantially orthogonal to the long axis of the core member.

12. The stent delivery system of clause 1, wherein the tabs interlock with the stent such that each tab is at least partially received within an aperture of the stent.

13. A stent delivery system, comprising:

a catheter having a lumen and an inner surface extending along the lumen;

a core member extending within the catheter lumen;

a plate, the plate comprising:

a first end face, a second end face, and a side surface extending between the first end face and the second end face; and

an aperture extending through the first and second end faces, the core member extending through the aperture such that the plate is rotatable about the core member; and

a bracket extending along the core member and over the plate, at least a portion of the bracket being positioned radially between the plate side surface and the conduit inner surface.

14. The stent delivery system of clause 13, wherein the deck-side surface comprises a plurality of projections separated by recesses.

15. The stent delivery system of clause 14, wherein the tabs interlock with the stent such that each tab is at least partially received within an aperture of the stent.

16. The stent delivery system of clause 14, wherein the one or more tabs comprises three or more tabs.

17. The stent delivery system of clause 13, wherein a maximum length of the first and second end surfaces is at least 5 times greater than a length of the side surface, the maximum length of the first and second end surfaces being substantially orthogonal to the length of the side surface.

18. The stent delivery system of clause 13, wherein the plate comprises at least one of a metal or a rigid polymer.

19. The stent delivery system of clause 13, wherein the plate is a first plate, the stent delivery system further comprising:

a second plate positioned about the core member and spaced apart from the first plate; and

a spacer positioned around the core member and between the first plate and the second plate.

20. The stent delivery system of clause 19, wherein the spacer comprises a cylindrical body having an end wall orthogonal to the long axis of the core member.

21. The stent delivery system of clause 19, wherein the first plate and the second plate are spaced apart from each other by a distance corresponding to the pore spacing of the stent.

22. A core assembly, comprising:

a core member;

a first rigid plate surrounding the core member;

a second rigid plate surrounding the core member and spaced apart from the first rigid plate; and

a spacer surrounding the core member, the spacer disposed between the first and second rigid plates.

23. The core member of clause 22, wherein the first rigid plate and the second rigid plate each comprise:

a first end face;

a second end face opposite the first end face;

a side surface extending between the first and second end surfaces and comprising a plurality of projections separated by recesses; and

an aperture extending through the first and second end faces, the aperture receiving the core member therethrough.

24. The core member of clause 23, wherein the one or more projections comprise three or more projections.

25. The core member of clause 23, wherein a maximum length of the first and second end faces is at least 5 times greater than a length of the side surface, the maximum length of the first and second end faces being substantially orthogonal to the length of the side surface.

26. The core member of clause 23, wherein the first end face and the second end face are substantially orthogonal to the long axis of the core member.

27. The core member of clause 22, wherein the first rigid plate and the second rigid plate comprise at least one of a metal or a rigid polymer.

28. The core member of clause 22, wherein the first rigid plate and the second rigid plate each have a thickness of between about 25-100 microns.

29. The core member of clause 22, wherein the spacer comprises a cylindrical body having an end wall orthogonal to the long axis of the core member.

30. A rigid plate for engaging a bracket, the plate comprising:

a first end face and a second end face;

a central opening extending through the rigid plate between the first end face and the second end face.

31. The rigid plate of clause 30, wherein the projection comprises a rounded edge.

32. The rigid plate of clause 30, wherein the one or more tabs comprises three or more tabs.

33. The rigid plate of clause 30, wherein the longest dimension of the first end face and the second end face is configured to fit within a 0.017", 0.021", or 0.027 "inner diameter catheter.

34. The rigid plate of clause 30, wherein a maximum length of the first and second end surfaces is at least 5 times greater than a length of the side surface, the maximum length of the first and second end surfaces being substantially orthogonal to the length of the side surface.

35. The rigid plate of clause 30, wherein the rigid plate comprises at least one of a metal or a rigid polymer.

36. The rigid plate of clause 30, wherein the side surface has a length between about 25 microns and 100 microns.

37. The rigid plate of clause 30, wherein the first end face and the second end face are substantially orthogonal to the major axis of the central opening.

Additional features and advantages of the technology will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the subject technology. The advantages of the technology will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the technology as claimed.

Drawings

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Emphasis instead being placed upon clearly illustrating the principles of the present technology. For ease of reference, throughout this disclosure, the same reference numbers may be used to identify the same or at least substantially similar or similar components or features.

Fig. 1 is a schematic illustration of a medical device delivery system configured according to some embodiments.

Fig. 2 is a side cross-sectional view of a medical device delivery system disposed within a body lumen according to some embodiments.

Fig. 3 is a side cross-sectional view of a core assembly of the medical device delivery system shown in fig. 2, according to some embodiments.

Fig. 4 is an enlarged side sectional view of the delivery system shown in fig. 2.

Fig. 5A is an enlarged perspective view of a coupling unit having a coupling according to some embodiments.

Fig. 5B is an enlarged perspective view of the coupling unit of fig. 5A with a bracket applied thereto.

Fig. 6A to 6C are side, end and perspective views, respectively, of an individual coupling piece of the coupling unit of fig. 5A and 5B.

Fig. 7 is a schematic cross-sectional view of the coupling and bracket of fig. 5B.

Detailed Description

Conventional stent couplings include soft "pads" that rely on a friction fit to secure a stent (such as a braided, knitted, or woven stent) against the inner wall of a catheter. Such friction fit pads may require several different pad diameters to accommodate a mix of different stent wire sizes. That is, within a given catheter size, the inner diameter of a compressed (braided, knitted or woven) stent housed in the catheter will vary based on the size (diameter) of the filaments, and possibly other parameters of the stent corresponding to different deployment sizes or target vessel sizes. This may require the use of different pad diameters to accommodate different stent sizes within a desired range (e.g., diameters of about 3.5 mm to 5 mm), which necessitates weaving pads of various diameters with very small size tolerances. Embodiments of the present technology can allow a single size coupling to be used with a relatively wide range of stent inner diameters within a given catheter size (e.g., 0.027", 0.021", or 0.017 "inner diameter catheters). For example, a coupler comprising a rigid plate having a plurality of projections separated by recesses may be used to secure a range of different stent sizes within a given catheter.

Specific details of several embodiments of the present technology are described herein with reference to fig. 1-7. Although many embodiments are described with respect to devices, systems, and methods for delivering stents and other medical devices, other applications and other embodiments in addition to those described herein are within the scope of the present technology. It should be noted that other embodiments in addition to those disclosed herein are also within the scope of the present technology. Additionally, embodiments of the present technology may have configurations, components, and/or processes different from those shown or described herein. Moreover, embodiments of the present technology may have configurations, components, and/or processes other than those shown or described herein, and these and other embodiments may not have the several configurations, components, and/or processes shown or described herein, without departing from the present technology.

As used herein, the terms "distal" and "proximal" define a position or orientation relative to a clinician or a clinician's control device (e.g., a handle of a delivery catheter). For example, the terms "distal" and "distally" refer to a location along the length of the device that is distal to or in a direction away from the clinician or clinician's control device. In a related example, the terms "proximal" and "proximally" refer to a location along the length of the device that is near or in a direction toward the clinician or clinician's control device. Headings provided herein are for convenience only and should not be taken as limiting the disclosed subject matter.

Selected examples of couplings for medical device delivery systems

Fig. 1-7 depict embodiments of a medical device delivery system that may be used to deliver and/or deploy a medical device, such as, but not limited to, a stent, into a hollow anatomical structure, such as a blood vessel. The stent may comprise a braided stent or other form of stent such as a woven stent, a knitted stent, a laser cut stent, a rolled stent, etc. The stent may optionally be configured to act as a "flow diverter" device for treating aneurysms, such as those found in blood vessels, including arteries in the brain or intracranial, or arteries in other locations within the body, such as peripheral arteries. The stent may optionally be similar to any version or size of PIPELINE sold by Medtronic neurovacular of Irvine, California USA^TMAn embolization device. The stent may alternatively include any suitable tubular medical device and/or other features, as described herein.

Fig. 1 is a schematic illustration of a medical device delivery system 100 configured in accordance with embodiments of the present technique. The system 100 may include an elongated tube or conduit 101 that slidably receives a core member 103, the core member 103 being configured to carry a stent 105 through the conduit 101. The depicted catheter 101 has a proximal region 107 and an opposite distal region 109, a lumen 111 extending from the proximal region 107 to the distal region 109, and an inner surface 113 defining the lumen 111, the distal region 109 being positionable at a treatment site within a patient. At the distal region 109, the catheter 101 has a distal opening 115, and the core member 103 can be advanced through the distal opening 115 past the distal region 109 to expand or deploy the stent 105 within the vessel 116. The proximal region 107 may include a catheter hub (not shown). The catheter 101 may define a generally longitudinal dimension extending between the proximal region 107 and the distal region 109. The longitudinal dimension need not be straight along a portion or any length thereof when the delivery system 100 is in use.

The core member 103 is configured to extend generally longitudinally through the lumen 111 of the catheter 101. Core member 103 may generally comprise any member or members that are flexible and have sufficient column strength to move stent 105 or other medical device through catheter 101. Core member 103 may thus comprise a wire, tube (e.g., hypotube), braid, coil, or other suitable member or members, or a combination of one or more wires, one or more tubes, one or more braids, one or more coils, or the like.

The system 100 can also include a coupling unit 117 (e.g., a device interface), the coupling unit 117 being configured to releasably retain the medical device or stent 105 relative to the core member 103. The coupling unit 117 is configured to underlie and engage the inner wall of the bracket 105. In this manner, the coupling unit 117 cooperates with the overlying inner surface 113 of the catheter 101 to grip the stent 105 such that the coupling unit 117 can move the stent 105 along the catheter 101 and within the catheter 101, e.g., distal and/or proximal movement of the core member 103 relative to the catheter 101 results in corresponding distal and/or proximal movement of the stent 105 within the catheter lumen 111.

In some embodiments, the coupling unit 117 may be configured to rotate about the core member 103. In some such embodiments, the coupling unit 117 can include a proximal restraint 119 and a distal restraint 121. The proximal and

distal constraints

119, 121 may be secured to the core member 103 to prevent or limit proximal or distal movement of the coupling unit 117 along the longitudinal dimension of the core member 103. One or both of the proximal and

distal constraints

119, 121 may have an outer diameter or other radially outermost dimension that is less than the outer diameter or other radially outermost dimension of the coupling unit 117 such that one or both of the

constraints

119, 121 do not contact the inner surface of the stent 105.

The coupling unit 117 can also include one or more couplers 123a-123c (e.g., stent engagement members), the one or more couplers 123a-123c disposed about the core member 103 and between the proximal and

distal restraints

119, 121 and the one or more spacers 125a-125 d. In the illustrated embodiment, links 123a-123c are spaced apart from one another by spacers 125b-125c, link 123a is spaced apart from proximal restraint 119 by spacer 125a, and link 123c is spaced apart from distal restraint by spacer 125d (which may be omitted in some embodiments of coupling unit 117). One, some, or all of the couplers 123a-123c may be rigid plates having a central aperture configured to receive the core member 103 therethrough. Links 123a-123c are configured to mechanically engage stent 105 such that links 123a-123c hold stent 105 from moving longitudinally relative to core member 103. Spacers 125a-125d may each be a substantially cylindrical body having an aperture configured to receive core member 103 therethrough. One or all of the spacers 125a-125d can have an outer diameter or other radially outermost dimension that is less than the outer diameter or other radially outermost dimension of the links 123a-123c such that the spacers 125a-125d do not contact the inner surface of the stent 105.

Although the embodiment shown in FIG. 1 includes three links 123a-123c and four spacers 125a-125d, the number of links and spacers may vary. In at least one embodiment, the coupling unit 117 includes only a single coupling without any spacer. In other embodiments, the number of couplings can vary, such as two, three, four, five, six, or more couplings separated by spacers.

In operation, stent 105 may be moved distally or proximally within catheter 101 by core member 103 and coupling unit 117. To move stent 105 out of catheter 101, core member 103 is moved distally while holding catheter 101 stationary, or core member 103 is held stationary while catheter 101 is withdrawn proximally. When core member 103 is moved distally and catheter 101 is held stationary, proximal restraint 119 presses against proximal-most spacer 125a and distally advances spacers 125a-125d and links 123a-123 c. The mechanical engagement between links 123a-123c and stent 105 causes stent 105 to move distally with links 123a-123c to deploy stent 105 out of distal region 109 of catheter 101. Conversely, to withdraw or otherwise move stent 105 into catheter 101, relative movement between core member 103 and catheter 101 is reversed as compared to moving stent 105 out of the catheter, such that a proximal region of distal restraint 121 compresses a distal region of distal-most spacer 125d and thereby causes spacers 125a-125d and links 123a-123c to retract relative to catheter 101. The mechanical engagement between links 123a-123c and stent 105 correspondingly holds stent 105 relative to core member 103 such that proximal movement of stent 105 relative to catheter 101 enables the stent 105 to be invaginated into the distal region 109 of catheter 101. This is useful when the stent 105 has been partially deployed and a portion of the stent remains disposed between at least one of the links 123a-123c (e.g., the most proximal link 123a) and the inner surface 113 of the catheter 101, as the stent 105 can be withdrawn into the distal opening 115 of the catheter 101 by moving the core member 103 proximally relative to the catheter 101 (and/or moving the catheter 101 distally relative to the core member 103). Nesting in this manner is still possible until links 123a-123c and/or catheter 101 have moved to the point where the proximal-most link 123a has passed over distal opening 115 of catheter 101 and stent 105 is released from between member 123a and catheter 101.

The couplers 123a-123c and spacers 125a-125d may be fixed to the core member 103 so as to be immovable in a longitudinal/sliding manner or in a radial/rotational manner with respect to the core member 103. Alternatively, the spacers 125a-125d and/or the couplers 123a-123c may be coupled to (e.g., mounted on) the core member 103 such that the spacers 125a-125d and/or the couplers 123a-123c may rotate about a longitudinal axis of the core member 103 and/or move or slide longitudinally along the core member 103. In such embodiments, the spacers 125a-125d and/or the couplers 123a-123c can each have a lumen or aperture that receives the core member 103 therein such that the spacers 125a-125d and/or the couplers 123a-123c can slide and/or rotate relative to the core member 103. Further, in such embodiments, the proximal and

distal restraints

119, 121 can be spaced apart a longitudinal distance along the core member 103 that is slightly greater than the combined length of the spacers 125a-125d and the links 123a-123c, so as to leave one or more longitudinal gaps between the proximal-most spacer 125a and the distal-most spacer 125d and the proximal and

distal restraints

119, 121, respectively. When present, the one or more longitudinal gaps allow the spacers 125a-125d and links 123a-123c to slide longitudinally along the core member 103 between the

constraints

119, 121. The range of longitudinal motion of the spacers 125a-125d and the links 123a-123c between the

restraints

119, 121 is approximately equal to the total combined length of the one or more longitudinal gaps.

Alternatively or in addition to one or more longitudinal gaps, the coupling unit 117 may include radial gaps between the outer surface of the core member 103 and the inner surfaces of the spacers 125a-125d and the couplers 123a-123 c. Such radial gaps may be formed when spacers 125a-125d and/or couplers 123a-123c are configured with holes that are slightly larger than the outer diameter of the corresponding portion of core member 103. When present, the radial gaps allow the spacers 125a-125d and/or links 123a-123c to rotate about the longitudinal axis of the core member 103 between the

constraints

119, 121. The presence of at least one minimum sized longitudinal gap on either side of the spacers 125a-125d and couplings 123a-123c may also facilitate rotatability of the spacers 125a-125d and couplings 123a-123 c.

Fig. 2-4 illustrate another embodiment of a medical device delivery system configured in accordance with embodiments of the present technique. As shown in fig. 2, the depicted medical device delivery system 200 may include an elongated tube or catheter 210 that slidably receives a core assembly 240, the core assembly 240 configured to carry a stent 201 through the catheter 210. FIG. 3 shows core assembly 240, with catheter 210 and vessel 202 not depicted for clarity. The depicted catheter 210 (see fig. 2 and 4) has a proximal region 212 and an opposite distal region 214, an inner lumen 216 extending from the proximal region 212 to the distal region 214, and an inner surface 218 facing the lumen 216, the distal region 214 being positionable at a treatment site within a patient. At the distal region 214, the catheter 210 has a distal opening (not shown) through which the core assembly 240 may be advanced over the distal region 214 to expand or deploy the stent 201 within the vessel 202. The proximal region 212 may include a catheter hub 222. The catheter 210 may define a generally longitudinal dimension a-a extending between the proximal region 212 and the distal region 214. The longitudinal dimension need not be straight along a portion or any length thereof when the delivery system 200 is in use.

The conduit 101/210 optionally may include a microcatheter. For example, catheter 101/210 optionally may include a MARKSMAN of any of a variety of lengths available from Medtronic neurovacular of Irvine, California USA^TMA conduit. The catheter 101/210 optionally can include a microcatheter having an inner diameter of about 0.030 inches or less and/or an outer diameter of 3French or less near the distal region 109/214. Alternatively or in addition to these specifications, the catheter 101/210 may include a microcatheter configured to percutaneously access the internal carotid artery or another location within the neurovasculature distal to the internal carotid artery with its distal opening 113.

The core assembly 240 may include a core member 260, the core member 260 being configured to extend generally longitudinally through the lumen 216 of the catheter 210. The core member 260 may have a proximal region or section 262 and a tip or distal region 264, which tip or distal region 264 optionally may include a tip coil 265. Core member 260 may further include an intermediate portion 266 between proximal region 262 and distal region 264 that is a portion of core member 260 onto which stent 201 is positioned or fitted or extends when core assembly 240 is in the pre-deployment configuration shown in fig. 2-4.

Core member 260 may generally comprise any member or members that are flexible and have sufficient column strength to move stent 201 or other medical device through catheter 210. Core member 260 may thus comprise a wire, tube (e.g., hypotube), braid, coil, or other suitable member or members, or a combination of one or more wires, one or more tubes, one or more braids, one or more coils, or the like.The embodiment of the core member 260 depicted in fig. 2-4 has a multi-member construction, including a proximal wire 268, a tube 270 (e.g., a hypotube) connected to a distal region of the proximal wire 268 at a proximal region, and a distal wire 272 connected to a distal region of the tube 270 at a proximal region. An outer layer 274 (which may include a layer of lubricious material, such as PTFE (polytetrafluoroethylene or TEFLON)^TM) Or other lubricious polymer) may cover a portion or all of the tube 270 and/or the proximal wire 268. The proximal wire 268 and/or the distal wire 272 may taper or vary in diameter along a portion or all of their length. The proximal wire 268 may include one or more fluorescent safety (fluoroform) markers 276, and such markers may be located on portions of the wire 268 not covered by the outer layer 274 (e.g., proximal to the outer layer 274). This portion of the wire 268 that is marked by the one or more markers 276 and/or proximal to any of the outer layers 274 may include a bare metal outer surface.

The core assembly 240 may also include a proximal coupling unit 282 and/or a distal coupling unit 290 that may interconnect the medical device or stent 201 with the core member 260. The proximal coupling unit 282 may include one or more coupling members 123a-123c configured to underlie the stent 201 and engage an inner wall of the stent. In this manner, the proximal coupling unit 282 cooperates with the overlying inner surface 218 of the catheter 210 to grip the stent 201 such that the proximal coupling unit 282 can move the stent 201 along the catheter 210 and within the catheter 210 (e.g., when a user pushes the core member 260 distally and/or pulls the core member proximally relative to the catheter 210), thereby causing corresponding distal and/or proximal movement of the stent 201 within the catheter lumen 216.

In some embodiments, the proximal coupling unit 282 may be similar to any of the versions or embodiments of the coupling unit 117 described above with respect to fig. 1. For example, the proximal coupling unit 282 may include a proximal constraint 119 and a distal constraint 121, the proximal and

distal constraints

119, 121 being fixed to the core member 260 (e.g., to the distal wire 272 thereof in the depicted embodiment) so as to be non-movable in a longitudinal/sliding manner or a radial/rotational manner relative to the core member 260. Proximal coupling unit 282 may also include a plurality of couplers 123a-123c separated by spacers 125a-125 d. The couplers 123a-123c and spacers 125a-125d can be coupled to (e.g., mounted on) the core member 260 such that the proximal coupling unit 282 can rotate about a longitudinal axis a-a of the core member 260 (e.g., of the distal wire 272) and/or move or slide longitudinally along the core member. One or both of the proximal and

distal restraints

119, 121 can have an outer diameter or other radially outermost dimension that is less than an outer diameter or other radially outermost dimension of the proximal coupling unit 282 such that one or both of the

restraints

119, 121 will tend not to contact the inner surface of the stent 201 during operation of the core assembly 240.

In the proximal coupling unit 282 shown in fig. 2-4, the stent 201 may be moved distally or proximally within the catheter 210 by the proximal coupling unit 282, and in some embodiments, the stent 201 may be sleeved back by the proximal coupling unit 282 after deployment from the distal opening portion of the catheter 210, in a manner similar to that described above with respect to the coupling unit 117 in fig. 1.

Optionally, when in the delivery configuration shown in fig. 2-4, the proximal edge of the proximal coupling unit 282 may be positioned just distal to the proximal edge of the stent 201. In some such embodiments, this enables looping back of stent 201 while the stent remains in catheter 210 for at least a few millimeters. Thus, for a stent 201 having a typical length, 75% or more collapsibility may be provided (i.e., the stent 201 may be collapsible when the stent 201 has been deployed by 75% or more).

The distal coupling unit 290 may include a distal engagement member 292, which distal engagement member 292 may take the form of, for example, a distal device cover or a distal stent cover (generally, a "distal cover"). The distal cover 292 may be configured to reduce friction between the medical device or stent 201 (e.g., a distal portion or region thereof) and the inner surface 218 of the catheter 210. For example, the distal cover 292 can be configured as a lubricious, flexible structure having a free first end or section 292a that can extend over at least a portion of the stent 201 and/or the intermediate portion 266 of the core member 260, and a fixed second end or section 292b that can be coupled (directly or indirectly) to the core member 260.

The distal cover 292 may have a first or delivery position, configuration, or orientation, wherein the distal cover may extend proximally relative to the distal tip 264, or from the second section 292b or the (direct or indirect) attachment of the distal cover to the core member 260, and at least partially surround or cover the distal portion of the stent 201. The distal cover 292 may be movable from a first or delivery orientation to a second or recapped position, configuration, or orientation (not shown), wherein the distal cover may be everted such that a first end 292a of the distal cover is positioned distally relative to a second end 292b of the distal cover 292 to enable recapping of the core assembly 240, whether with or without the stent 201 carried thereby.

The distal cover 292, in particular the first end 292a thereof, may include one or more flexible, generally longitudinally extending strips, wings or elongated portions coupled to or integrally formed with the second end 292 b. The distal cover 292 may be manufactured or otherwise cut from a tube of the material selected for the distal cover or from multiple radial portions of such a tube. In such embodiments, the first section 292a may be formed as a plurality of longitudinal strips cut from the tube, and the second section 292b may be an uncut (or similarly cut) length of tube. Thus, the second section 292b and the proximally extending strip of the first section 292a may form a single unitary device or structure. In some embodiments, the distal cover 292 includes only one or no more than two straps, wings, or elongated portions.

In some embodiments, the distal cover 292 may comprise a tube or a longitudinally slotted tube, and the first section 292a may comprise two or more semi-cylindrical or partially cylindrical strips or tube portions separated by a corresponding number of generally parallel longitudinally-oriented cuts or spaces formed or otherwise positioned in the sidewall of the tube. Thus, when in the pre-expanded state, as shown in fig. 2-4, the first section 292a may generally have the shape of a longitudinally split or longitudinally grooved tube extending radially between or radially interposed between the outer surface of the stent or device 200 and the inner surface 218 of the catheter 210.

In various embodiments, the bands, wings, or elongated portions of the first section 292a may collectively span the entire circumference of the outer surface of the stent 201 (e.g., where the cuts between the bands are slits having a substantially zero width), or be sized slightly less than the entire circumference (e.g., where the cuts between the bands are slots having a non-zero width). According to some embodiments, the width of the strip, wing or elongate portion of the first section 292a may be between about 0.5mm and about 4 mm. The width may be about 0.5mm to about 1.5 mm. According to some embodiments, the width may be about 1 mm.

The strip, wing or elongate portion of the first section 292a may also extend longitudinally over at least a portion of the distal portion of the stent 201. In various embodiments, the first section 292a may extend a distance of between about 1mm and about 3mm, or between about 1.5mm and about 2.5mm, or about 2mm on the distal portion of the stent.

The first and

second sections

292a, 292b may define an overall length of the distal cover 292. In some embodiments, the overall length may be between about 4mm and about 10 mm. The overall length may also be between about 5.5mm and about 8.5 mm. In some embodiments, the overall length may be about 7 mm.

The strips of the first section 292a may have a substantially uniform size. For example, the first section 292a may include two bands each spanning approximately 180 degrees, three bands each spanning approximately 120 degrees, four bands each spanning approximately 90 degrees, or otherwise divided to collectively cover all or a portion of the circumference of the stent, etc. Alternatively, the strips may differ in angular sizing and coverage area without departing from the scope of the present disclosure. In one embodiment, only two strips or tube portions are employed in the first section 292 a. Using only two strips may facilitate radial expansion, distal movement, and/or folding or everting of the first section 192a, as discussed herein, while minimizing the number of free or un-accommodated strips in the vessel lumen and any possibility of damaging the vessel due to contact between the strips and the vessel wall.

The distal cover 292 may use a lubricious and/or hydrophilic material such as PTFE or

But may be made of other suitable lubricious materials or lubricious polymers. The distal cover may also include a radiopaque material that may be blended into the primary material (e.g., PTFE) to impart radiopacity. The distal cover 292 may have a thickness between about 0.0005 "and about 0.003". In some embodiments, the distal cover may be one or more PTFE strips having a thickness of about 0.001 ".

The distal cover 292 (e.g., the second end 292b thereof) may be fixed to the core member 260 (e.g., to the distal wire 272 or the distal tip 264 thereof) so as to be non-movable in a longitudinal/sliding manner or a radial/rotational manner relative to the core member 260. Alternatively, as depicted in fig. 2-4, the distal cover 292 (e.g., the second end 292b thereof) may be coupled to (e.g., mounted on) the core member 260 such that the distal cover 292 may rotate about the longitudinal axis a-a of the core member 260 (e.g., of the distal wire 272) and/or move or slide longitudinally along the core member. In such embodiments, the second end 292b may have a lumen that receives the core member 260 therein such that the distal cover 292 may slide and/or rotate relative to the core member 260. Additionally, in such embodiments, the distal coupling unit 290 can further include a constraint 294 secured to the core member 260 proximal to the distal cover 292 (its second end 292b), and/or a constraint 296 secured to the core member 260 distal to the distal cover 292 (its second end 292 b). The proximal and

distal restraints

294, 296 may be spaced apart a longitudinal distance along the core member 260 that is slightly greater than the length of the second end 292b so as to leave one or more longitudinal gaps 297 between the second end 292b and one or both of the proximal and distal restraints 194, 196 depending on the position of the second end 292b therebetween. When present, the one or more longitudinal gaps 197 allow the second end 292b and/or distal cover 292 to slide longitudinally along the core member 260 between the

restraints

294, 296. The range of longitudinal movement of the second end 292b and/or the distal cover 292 between the

restraints

294, 296 is approximately equal to the total length of the one or more longitudinal gaps 297.

Instead of or in addition to one or more longitudinal gaps 297, distal coupling unit 290 may include a radial gap 298 between an outer surface of core member 260 (e.g., distal wire 272) and an inner surface of second end 292 b. Such a radial gap 298 may be formed when the second end 292b is configured with an inner lumen diameter that is slightly larger than the outer diameter of the corresponding portion of the core member 260. When present, the radial gap 298 allows the distal cover 292 and/or the second end 292b to rotate about the longitudinal axis a-a of the core member 260 between the

constraints

294, 296. The presence of at least one extremely small sized longitudinal gap 297 on either side of the second end 292b may also facilitate rotatability of the distal cover.

One or both of the proximal and

distal restraints

294, 296 can have an outer diameter or other radially-outermost dimension that is less than an outer diameter or other radially-outermost dimension of the distal cover 292 (e.g., prior to deployment) such that one or both

restraints

294, 296 will tend not to press or contact the inner surface 218 of the catheter 210 during operation of the core assembly 240.

In the embodiment depicted in fig. 2-4, the second end 292b of the distal cover 292 comprises an inner cuff 292c, which may comprise a coil (metal or polymer) as depicted, or other substantially rigid, tubular or cylindrical inner member, such as a short piece of relatively stiff polymer or metal tubing. The inner cuff 292c may be housed in an annular housing or one or more ferrules formed by the second end 292b or otherwise attached to or integrated into the second end 292b in a manner that tends to keep the inner diameter of the distal cover 292 in the second end 292b greater than the outer diameter of the adjacent portion of the core member 160 (or wire 172 thereof). In other words, the ferrule 292c may help maintain the radial gap 298 between the inner diameter of the second end 292b and the outer diameter of the core member 260 or distal wire 272.

The annular housing or one or more collars of the second end 292b may be formed by: a portion of a sheet or tube of distal covering material (e.g., PTFE) is wrapped around the sidewall of the cuff 292c and through the lumen thereof, and an end of the wrapped portion of the sheet or tube is adhered, glued, or thermally bonded to an adjacent proximally extending portion of the sheet or tube. Thereby forming two layers adhered together on the proximal side of the cuff 292 c. Where the distal cover material comprises PTFE, unsintered PTFE may be used to enable the two portions of material to be bonded together with heat and pressure, which is not generally possible with "plain" or sintered PTFE.

In operation, the distal cover 292, and more particularly the first section 192a, may substantially cover and protect the distal region 304 of the stent 201 as the stent 201 is moved distally within the catheter 110. The distal cover 192 may serve as a support or cushioning layer that, for example, inhibits the filament ends of the distal region 304 of the stent 201 (where the stent 201 comprises a braided stent) from contacting the inner surface 118 of the catheter 110, which contact may damage the stent 201 and/or the catheter 110, or otherwise compromise the structural integrity of the stent 201. Since the distal cover 192 may be made of a lubricious material, the distal cover 192 may exhibit a low coefficient of friction that allows the distal region 304 of the stent 201 to slide axially within the catheter 110 with relative ease. The coefficient of friction between the distal cover and the catheter inner surface may be between about 0.02 and about 0.4. For example, in embodiments where the distal cover and catheter are formed of PTFE, the coefficient of friction may be about 0.04. Such embodiments may advantageously improve the ability of the core assembly to pass through a catheter, particularly in tortuous vasculature.

In addition, as shown in fig. 2-4, in the first position, configuration, or orientation, at least a portion of the distal cover 292 may extend at least partially radially between or be radially interposed between the distal portion of the stent 201 and the inner surface 218 of the catheter 210. In the first orientation, the first section 292a of the distal cover 292 may extend in a proximal orientation from the second section 292b to a point where the first section is interposed between the distal portion of the stent 201 and the inner surface 218 of the catheter 210. In this orientation, the first section of the distal cover may assume a "proximally-oriented" position or configuration.

Structures other than the embodiments of the distal cover 292 described herein may be used in the core assembly 240 and/or the distal coupling unit 290 to cover or otherwise interact with the distal region 304 of the stent 201. For example, a protective coil or other sleeve having a longitudinally oriented proximally opening lumen may be employed. In other embodiments, the distal coupling unit 290 may omit the distal cover 292, or the distal cover may be replaced with components similar to the proximal coupling unit 282. Where a distal cover 292 is employed, it may be attached to the distal tip coil 265 (e.g., by wrapping around and encapsulating a portion or all of the coil 265) or adhered or coupled to the outer surface of the coil by an adhesive or a surrounding shrink tube. The distal cover 292 may be coupled (directly or indirectly) to other portions of the core assembly 240, such as the distal wire 272.

In embodiments of the core assembly 240 employing both the rotatable proximal coupling unit 282 and the rotatable distal cover 292, the stent 201 may be rotatable relative to the core member 260 about its longitudinal axis a-a due to the rotatable proximal coupling unit 282 and the distal cover 292 (which are rotatably connected). In such embodiments, the stent 201, proximal coupling unit 282, and distal cover 292 may be rotated together about the core member in this manner. Because rotation of the stent, proximal engagement member, and distal cover about the core member counteracts the tendency of the vessel to twist the stent and/or core assembly, the core assembly 240 may be more easily advanced through tortuous vessels as the stent 201 is able to rotate about the core member 260. In addition, because the user's input thrust is not diverted to twist the stent and/or core member, the required thrust or delivery force is reduced. The tendency of the twisted stent and/or core member to suddenly untwist or "whip" as the stent is untwisted or deployed and the tendency of the twisted stent to resist expansion as it is deployed are also reduced or eliminated. Additionally, in some such embodiments of the core assembly 240, a user may "manipulate" the core assembly 240 by the tip coil 265, particularly if the coil 265 is bent at an angle in its unstressed configuration. By rotating the distal region 264 of the core member 260, such a coil tip may be rotated about the axis a-a relative to the stent 201, the coupling unit 282, and/or the distal cover 292. Thus, a user may point the coil tip in a desired direction of travel of the core assembly, and as the core assembly is advanced, the tip will guide the core assembly in a selected direction.

Fig. 5A is an enlarged perspective view of the coupling unit 517 of the medical device delivery system 500. Fig. 5B shows a coupling unit 517 with a bracket 505 overlaid thereon. The coupling unit 517 includes a plurality of coupling members 523a-523c separated by a plurality of spacers 525a-525 d. A proximal restraint 519 is disposed proximal to the proximal-most spacer 525 a. The proximal restraint 519 and the coupling unit 517 are disposed about the core member 503. Fig. 6A to 6C are a side view, an end view, and a perspective view, respectively, of the coupling member 523 of the coupling unit 517 shown in fig. 5A and 5B. Fig. 7 is a schematic cross-sectional view of the coupling 523 engaging the stent 505. The depicted stent 505 is woven (although other types of stents as disclosed elsewhere herein may be used) and includes mesh 563 forming a plurality of pores 565 separated by points at which the filaments of the weave intersect or intersect.

Referring also to fig. 5A-7, each link 523 may have a plate-like configuration having first and second end faces 551, 553 and a side surface 555 extending between the first and second end faces 551, 553. In the assembled delivery system 500, the first end face 551 and the second end face 553 may be oriented and maintained substantially orthogonal to the long axis of the core member 503. This can be achieved by: the spacers 525a-525d are configured to have distal and proximal end faces that are orthogonal to the longitudinal axis of each spacer 525 (and/or core member 503) and/or to minimize the amount of longitudinal movement space (or "play") between the spacers and the links of the coupling unit 517. Each coupling forms a plurality of radially extending projections 557 separated by depressions 559. In the embodiment shown, there are four protrusions 557 separated by four depressions 559. However, in other embodiments, the number of projections may vary, such as two, three, four, five, six, seven, or more projections separated by a corresponding number of recesses.

The protrusion 557 may include rounded edges and the depression 559 may include a rounded recess. The rounded edges may reduce scraping of the projections 557 against the inner wall of the overlying catheter 567 during use of the delivery system 500, which reduces particle generation and reduces damage to the catheter 567. When the delivery system 500 is used with a braided stent, such as the depicted stent 505, the recesses 559 can be sized to accommodate the thickness of the braid wire intersections such that each protrusion can extend at least partially into an aperture 565 of the stent 505 between adjacent wire intersections, and the wire intersections around the aperture 565 can be at least partially received within the recesses 559 of the coupling. In other embodiments, the projections and/or depressions may take other forms, such as having sharper or flatter peaks formed by the projections. The links 523 may be fabricated by photochemical etching, laser cutting, molding, machining, or other suitable process.

Each link 523 includes an opening or central aperture 561 configured to receive the core member 503 therethrough. As previously mentioned, the opening of the bore 561 may be larger than the diameter of the core member 503 such that the link 523 may rotate about the long axis of the core member 503.

The link 523 may be made to have a relatively thin and/or plate-like configuration. Such a configuration may facilitate the formation of projections 557 that are small enough to fit within the apertures 565 of the stent 505. Thus, the coupling 523 can be characterized by a maximum diameter D along the first and second end faces 551, 553, and a thickness T measured along the side surface 555. In some embodiments, diameter D is at least five times greater than thickness T. In at least one embodiment, the thickness T is between about 25 microns and 100 microns or between 25 microns and 75 microns, such as about 50 microns (about 0.002 ").

To effectively push or pull the stent 505 along the conduit 567, the link 523 can be made rigid (e.g., incompressible by the forces encountered in typical use of the delivery system). The rigidity of the links 523 may be attributed to their material composition, their shape/configuration, or both. In some embodiments, the coupling 523 is made of metal (e.g., stainless steel, nitinol, etc.) or a rigid polymer (e.g., polyimide), or both. In some embodiments, even if the coupling is made of a rigid material, the coupling itself may be non-rigid and at least partially compressible based on structural characteristics.

The spacer 525 may be a substantially cylindrical body having an outer diameter less than the maximum outer diameter of the coupling 523. In some embodiments, the spacer 525 includes a central aperture (not shown) sized and configured to allow the spacer 525 to be rotatably mounted over the core member 503. As previously mentioned, the spacer 525 may have an end wall that is orthogonal to the long axis of the core member 503. These orthogonal end walls may help to maintain the orthogonal orientation of the link 523 relative to the core member 503 to prevent loss of engagement with the bracket 505.

In some embodiments, the coupling unit 517 may be configured to engage only a proximal portion of the stent 505 (e.g., only a proximal half, only a proximal-most third, etc.). In other embodiments, the coupling unit 517 may engage the stent 505 along substantially its entire length.

The link 523 may mechanically interlock or engage with the stent 505 such that each projection 557 is at least partially received within one of the apertures 565. The spacers may be configured to have a length such that the projections 557 of adjacent links 523 (e.g., link 523a and adjacent link 523b) are longitudinally spaced apart a distance equal to the "pore spacing" of the stent (the distance between the centers of longitudinally adjacent pores 565) when the stent 505 is at the inner diameter of the conduit 567, or more typically, equal to an integer multiple of the pore spacing of the stent 505. Thus, each projection can extend into and engage one of the apertures 565 of the bracket 505. In some embodiments, adjacent links 523 can engage longitudinally adjacent apertures 565 of stent 505; in other embodiments, adjacent links 523 engage apertures 565 that are not longitudinally adjacent, but are longitudinally spaced apart by one or more intervening apertures. Thus, the first link 523a and the second link 523b may be spaced from one another by a longitudinal distance corresponding to the aperture pitch of the rack 505, or by a longitudinal distance corresponding to an integer multiple of the aperture pitch.

Interaction between the projections 557 and the apertures 565 may create a mechanical interlock between the bracket links 523 and the apertures 565. This is in contrast to conventional compressible pads which resiliently push against the entire stent, including the wire intersections. In at least some embodiments, the mechanical interlock provided by the links 523 secures the stent 505 without pressing against the wire intersections of the stent 505. In some embodiments, the coupling 523 is configured to secure a range of different stent sizes within a given catheter size (e.g., within 0.017", 0.021", or 0.027 "catheter (inner diameter)).

It is noted that various components of the delivery system 500 of fig. 5A-7 may be incorporated into the delivery system 100 of fig. 1 or the delivery system 200 of fig. 2-4. For example, any of the disclosed embodiments of coupling unit 517 may be used as a coupling unit of delivery system 100 or delivery system 200. Similarly, any embodiment of coupling 523 can be used as one or more couplings of delivery system 100 or delivery system 200, and/or any embodiment of spacer 525 can be used as one or more spacers of delivery system 100 or delivery system 200.

Conclusion

The disclosure is not intended to be exhaustive or to limit the technology to the precise forms disclosed herein. While specific embodiments have been disclosed herein for purposes of illustration, various equivalent modifications may be made without departing from the technology, as will be recognized by those skilled in the relevant art. In some instances, well-known structures and functions have not been shown and/or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Although the steps of the methods may be presented herein in a particular order, in alternative embodiments, the steps may have another suitable order. Similarly, certain aspects of the technology disclosed in the context of particular embodiments may be combined or eliminated in other embodiments. Moreover, while advantages associated with certain embodiments have been disclosed in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages or other advantages disclosed herein in order to fall within the scope of the present technology. Accordingly, the present disclosure and associated techniques may encompass other embodiments not explicitly shown and/or described herein.

Throughout this disclosure, the singular terms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Similarly, with respect to a list of two or more items, unless the word "or" is expressly limited to mean only a single item exclusive of other items, the use of "or" in such a list is to be interpreted as including (a) any single item in the list, (b) all items in the list, or (c) any combination of items in the list. In addition, throughout this disclosure, use of the terms "comprising" and the like is intended to mean including at least one or more of the recited features, such that any greater number of the same features and/or one or more additional types of features are not excluded. Directional terms such as "upper", "lower", "front", "rear", "vertical" and "horizontal" may be used herein to express and clarify the relationship between the various elements. It should be understood that such terms are not intended to imply an absolute orientation. Reference herein to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, operation, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present technology. Thus, appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, the various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.

Claims

1. A stent delivery system comprising:

a core member having a distal section;

a coupling unit positioned around a distal segment of the core member, the coupling unit comprising:

a proximal restraint coupled to the distal section of the core member;

a distal restraint coupled to the distal section of the core member at a location distal of the proximal restraint;

two or more plates slidably coupled to the distal section of the core member between the proximal and distal constraints; and

one or more spacers coupled to the distal section of the core member between the proximal and distal constraints,

wherein the proximal and distal restraints are spaced apart a longitudinal distance along the core member that is greater than a combined length of the two or more plates and the one or more spacers coupled to the distal section of the core member between the proximal and distal restraints; and

a bracket extending along a distal section of the core member such that an inner surface of the bracket is engaged by at least one of the two or more plates.

2. The stent delivery system of claim 1, wherein the longitudinal distance is such that a plate can slide longitudinally along a distal section of the core member relative to the proximal and distal restraints.

3. The stent delivery system of claim 1, wherein the one or more spacers comprise a spacer disposed between two plates.

4. The stent delivery system of claim 1, wherein:

the two or more plates include a first plate, a second plate, and a third plate,

the one or more spacers include a first spacer and a second spacer, and

the first spacer is disposed between the first plate and the second plate, and the second spacer is disposed between the second plate and the third plate.

5. The stent delivery system of claim 4, wherein the proximal and distal constraints are spaced apart a longitudinal distance along the core member that is greater than a combined length of the first, second, and third plates and the first and second spacers.

6. The stent delivery system of claim 1, wherein at least one protrusion of the two or more plates interlocks with the stent such that the protrusion is at least partially received within an aperture of the stent.

7. The stent delivery system of claim 1, wherein the two or more plates are spaced apart from each other by a distance corresponding to a distance between centers of longitudinally adjacent pores of the stent.

8. A stent delivery system comprising:

a catheter having a lumen and an inner surface extending along the lumen;

a core member extending within a lumen of the catheter;

first and second couplers slidably mounted to the core member, each of the first and second couplers comprising:

an aperture extending through the first and second end faces, the core member extending through the aperture, the aperture defining a radial gap between an outer surface of the core member and an inner surface of the coupling;

one or more spacers mounted on the core member;

a proximal restraint mounted on the core member at a location proximal of the first link, the second link, and the one or more spacers;

a distal restraint mounted on the core member at a location distal of the first link, the second link, and the one or more spacers, the distal restraint being spaced apart from the proximal restraint a longitudinal distance greater than a combined length of the first link, the second link, and the one or more spacers; and

a support extending along the core member and radially disposed between an inner surface of the conduit and the first and second couplers.

9. The stent delivery system of claim 8, wherein the stent comprises a mesh forming a plurality of apertures, and wherein the first and second links are spaced apart from each other by a distance corresponding to a distance between centers of longitudinally adjacent apertures of the stent.

10. The stent delivery system of claim 8, wherein a radially outermost dimension of the spacer is less than a radially outermost dimension of the first and second links.